FYI: the dmesg message fix should be already included in 5.0-rc1:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/amd/display/dc/core/dc_link.c?h=v5.0-rc1&id=8c9d90eebd23b6d40ddf4ce5df5ca2b932336a06